The anti-inflammatory effect of honokiol on neutrophils: mechanisms in the inhibition of reactive oxygen species production

Eur J Pharmacol. 2003 Aug 15;475(1-3):19-27. doi: 10.1016/s0014-2999(03)02121-6.


Reactive oxygen species produced by neutrophils contribute to the pathogenesis of focal cerebral ischemia/reperfusion injury and signal the inflammatory response. We have previously shown that honokiol, an active principle extracted from Magnolia officinalis, has a protective effect against focal cerebral ischemia/reperfusion injury in rats that paralleled a reduction in reactive oxygen species production by neutrophils. To elucidate the underlying mechanism(s) of the antioxidative effect of honokiol, peripheral neutrophils isolated from rats were activated with phorbol-12-myristate-13-acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in the presence or absence of honokiol. In this study, we found that honokiol inhibited PMA- or fMLP-induced reactive oxygen species production by neutrophils by three distinct mechanisms: (1) honokiol diminished the activity of assembled-NADPH oxidase, a major reactive oxygen species producing enzyme in neutrophils by 40% without interfering with its protein kinase C (PKC)-dependent assembly; (2) two other important enzymes for reactive oxygen species generation in neutrophils, i.e., myeloperoxidase and cyclooxygenase, were also inhibited by honokiol by 20% and 70%, respectively; and (3) honokiol enhanced glutathione (GSH) peroxidase activity by 30%, an enzyme that triggers the metabolism of hydrogen peroxide (H2O2). These data suggested that honokiol, acting as a potent reactive oxygen species inhibitor/scavenger, could achieve its focal cerebral ischemia/reperfusion injury protective effect by modulating enzyme systems related to reactive oxygen species production or metabolism, including NADPH oxidase, myeloperoxidase, cyclooxygenase, and GSH peroxidase in neutrophils.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / chemistry
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Biphenyl Compounds / chemistry
  • Biphenyl Compounds / pharmacology*
  • Lignans*
  • Male
  • Neutrophils / drug effects*
  • Neutrophils / metabolism
  • Rats
  • Rats, Long-Evans
  • Reactive Oxygen Species / metabolism*


  • Anti-Inflammatory Agents, Non-Steroidal
  • Biphenyl Compounds
  • Lignans
  • Reactive Oxygen Species
  • honokiol